This invention applies to Oxo synthesis reactors and specifically to steels which are particularly adapted for the manufacture of reactors capable of resisting the parasitic effects of Oxo synthesis. The term "reactor" means the entire apparatus in which the reaction cycle is carried out. The invention also relates to the reactors made from these steels.
Oxo synthesis is known as the hydroformylation reaction which consists in reacting a mixture of carbon oxide and hydrogen with an olefin containing "n" carbon atoms in the presence of a catalyst which is usually cobalt-based. In the course of this reaction, aldehydes and alcohols containing "n+1" carbon atoms are formed.
This reaction is carried out in reactors of known design and dimensions which must withstand high pressures. One type of reactor which is suitable for this reaction is described in British Pat. No. 920,417. These reactors are generally made from ordinary steel, like any other reactor which is required to withstand high pressures.
However, in use, it is found that after a certain period of service, which can vary from several months to two years, cracks and occasionally serious fractures occur in these reactors which can cause grave accidents when these defects occur in an industrial plant required to operate under pressures of several hundred bars.
Although the exact reasons for these defects are not presently known, it is believed that they are of both chemical and metallurgical origin.
In the latter case, in particular, they could be due to the use of an unsuitable metal. The phenomena of corrosion resulting from the Oxo reaction products and/or from the reaction itself which cause the metal of the reactor to become fragile are not at all well understood, and therefore this supposition is the result of research carried out with a view to finding an alloy for producing a reactor in which the Oxo reaction could be performed with the maximum safety and without danger of premature wear of the reactor.